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Unformatted text preview: rations, and their dependencies in Figure 7 -5 and a copy of what such a sequencing Figure 7-4. PERT chart showing task dependency relation. looks like in Figure 7-6. Also, for those who have access to Project, we have included a copy of the example project scheduling database on the CD included with this book. It is in the file named example.mpp . Most of what appears in the table in Figure 7-5 is self-explanatory, but the way the dependencies are expressed may need a little explaining. What is shown in Figure 7-5 is part of the Entry table from Project. The Entry table is one of several tables that can be obtained from Project. As previously mentioned, it can be seen by clicking on the View control button at the top of the Project window and then selecting the Table option. Thereafter, select the Entry option. Project displays the dependencies in a column labeled Predecessors. It does this because the way Project displays a dependency is to list the dependent task and then, in the dependent task's Predecessors column, lists all the preceding tasks on which the dependent task depends. It also describes the type of dependency for each of the predecessor tasks. For instance, the Page 176 Figure 7-5. Task list for example project. Page 177 third dependency listed is for Siteprep 3. Its Predecessor column contains the cryptic symbols "2SS+5 days." This means Siteprep 3 depends on the second task in the list (the one labeled 2, that is, Siteprep 2), and the dependency is a start-to-start dependency (denoted "SS" in the table). In addition, there is a five-day lag time before Siteprep 3 can be started after Siteprep 2 is started. Adding the lag time part of the dependency is done at the same time you specify the dependency type in PERT Chart View, as explained earlier. The same window that allows you to choose the dependency type (e.g., start-to-start) allows you also to specify the lag time associated with a dependency. Some tasks, such as Task Number 17 (Frame 5), depend on more than one other task. Task Number 17 is also an example of a task that depends on two other tasks that were added to the task list after Task Number 17 was entered. Project assigns sequence numbers to the tasks as they are entered. Since Task Number 17 depends on tasks 18 and 38, it is clear that these tasks were entered after Task Number 17 was entered. Figure 7-6 shows what the task sequencing looks like when all the information in Figure 7-5 has been entered into the example project database. The reader may be wondering how to get around entering all these durations at this time, since this is not part of task sequencing. Task sequencing is concerned only with determining which tasks precede which other tasks. The lag time constraints for dependencies, however, can properly be considered part of task sequencing. The reason for entering the durations in this example was to show how Project prefers to operate. It is difficult to use Project strictly for task sequencing. Project does not have the concept of task sequencing and i...
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This note was uploaded on 01/11/2011 for the course ACC 9 taught by Professor Yeetan during the Spring '10 term at Sunway University College.
- Spring '10